Qicen Tang

Li Cu, an ordinary high school student, is suddenly attacked by a mysterious man who leaves a strange mark on his back. During treatment, he meets Dr. Liang Wan, who helps him uncover the man's identity with the assistance of Wang Meng. Upon returning to Liang Wan's home, they find Wu Xie waiting outside, urging Li Cu to join him on a journey to the desert. Once there, a series of baffling incidents unfold.

A series of serial killings is exposed and creates a stir among the public. A killer called "Darker" has been leaving a death notification card after killing scumbags who evaded the law. To counter the provocation of the mysterious killer, the police creates a special investigation team.